If all you want to do is to show some URL, this
is overkill. Just use HtmlBrowser.URLDisplayer.showURL(java.net.URL) instead. Using HtmlBrowser
is appropriate mainly if you want to embed a web browser in some other GUI component
(if the user has selected an external browser, this will fall back to a simple Swing
renderer). Similarly Impl (coming from a Factory) is the lower-level
renderer itself (sans toolbar).

Summary: for client use, try URLDisplayer.showURL, or for more control
or where embedding is needed, create an HtmlBrowser. For provider use,
create a Factory and register an instance of it to lookup.